NTA JEE Main 9th April 2019 Shift 2

The specific heats, C$$_p$$ and C$$_v$$ of a gas of diatomic molecules, A, are given (in units of J mol$$^{-1}$$ K$$^{-1}$$) by 29 and 22, respectively. Another gas of diatomic molecules, B, has the corresponding values 30 and 21. If they are treated as ideal gases, then:

A massless spring (k = 800 N/m), attached with a mass (500 g) is completely immersed in 1 kg of water. The spring is stretched by 2 cm and released so that it starts vibrating. What would be the order of magnitude of the change in the temperature of water when the vibrations stop completely? (Assume that the water container and spring receive negligible heat and specific heat of mass = 400 J/kg K, water = 4184 J/kg K)

Two cars A and B are moving away from each other in opposite directions. Both the cars are moving with speed of 20 m s$$^{-1}$$ with respect to the ground. If an observer in car A detects a frequency 2000 Hz of the sound coming from car B, what is the natural frequency of the sound source in car B? (speed of sound in air = 340 m s$$^{-1}$$)

A string 2.0 m long and fixed at its ends is driven by a 240 Hz vibrator. The string vibrates in its third harmonic mode. The speed of the wave and its fundamental frequency is:

Four point charges -q, +q, +q and -q are placed on y-axis at y = -2d, y = -d, and y = +2d, respectively. The magnitude of the electric field E at a point on the x-axis at x = D, with D >> d, will behave as:

The parallel combination of two air filled parallel plate capacitors of capacitance C and nC is connected to a battery of voltage, V. When the capacitors are fully charged, the battery is removed and after that a dielectric material of dielectric constant K is placed between the two plates of the first capacitor. The new potential difference of the combined system is:

A metal wire of resistance 3 $$\Omega$$ is elongated to make a uniform wire of double its previous length. This new wire is now bent and the ends joined to make a circle. If two points on this circle make an angle 60° at the center, the equivalent resistance between these two points will be:

The resistance of a galvanometer is 50 ohm and the maximum current which can be passed through it is 0.002 A. What resistance must be connected to it in order to convert it into an ammeter of range 0 - 0.5 A?

In a conductor, if the number of conduction electrons per unit volume is $$8.5 \times 10^{28}$$ m$$^{-3}$$ and mean free time is 25 fs (femto second), it's approximate resistivity is: ($$m_e = 9.1 \times 10^{-31}$$ kg)

Two coils 'P' and 'Q' are separated by some distance. When a current of 3 A flows through coil 'P', a magnetic flux of $$10^{-3}$$ Wb passes through 'Q'. No current is passed through 'Q'. When no current passes through 'P' and a current of 2 A passes through 'Q', the flux through 'P' is: